Prosthetic spinal disc nucleus having selectively coupled bodies

A method of manufacturing a prosthetic spinal disc nucleus for implantation into a nucleus cavity defined by an opposing pair of vertebrae and an anulus, the method including:

• forming a first prosthetic body having sufficient structural integrity for separating an opposing pair of vertebrae and a volume that is less than a volume of a nucleus cavity;
• forming a second prosthetic body having sufficient structural integrity for separating an opposing pair of vertebrae and a volume that is less than a volume of a nucleus cavity;
• and
• providing a coupling device to selectively couple the first prosthetic body to the second prosthetic body such that a distance between the first and second prosthetic bodies is variable in a first state, and relatively fixed in a second state, at least a portion of the coupling device being connected to both the first and second prosthetic bodies immediately following implantation.

A method of implanting a prosthetic spinal disc nucleus into a nucleus cavity defined by an opposing pair of vertebrae and an anulus, the prosthetic spinal disc nucleus including a first prosthetic body and a second prosthetic body, each of the prosthetic bodies having sufficient structural integrity to separate the opposing pair of vertebrae and a volume that is less than a volume of the nucleus cavity, the method including:

• providing a coupling device to selectively couple the first prosthetic body to the second prosthetic body;
• forming an opening in the anulus;
• inserting the first prosthetic body into the nucleus cavity through the opening in the anulus, the coupling device being configured such that the second prosthetic body does not impede insertion of the first prosthetic body and at least a portion of the coupling device being connected to the first prosthetic body immediately after insertion;
• lodging the first prosthetic body in the nucleus cavity;
• inserting the second prosthetic body into the nucleus cavity such that at least a portion of the coupling device is connected to the second prosthetic body immediately after insertion;
• and
• positioning the coupling device such that the first prosthetic body prevents displacement of the second prosthetic body back through the opening in the anulus.